The present invention relates to a tone data generation method and apparatus and tone synthesis method and apparatus which can be suitably used in tone generation apparatus, such as electronic musical instruments and automatic performance apparatus, to permit high-quality control of tone elements, such as the amplitude and pitch, included in sampled waveform data.
There have been known so-called samplers which store sampled waveform data of tones in a memory and use the memory-stored waveform data as tone sources of an electronic musical instrument or the like. Where tones are synthesized using the sampled waveform data, it is desirable to freely control/adjust tone elements, such as an amplitude and pitch, when the tones are to be reproduced, rather than simply reproducing the sampled original waveform itself. As a technique designed for such improved tone synthesis, Japanese Patent Application Laid-open Publication No. HEI-5-297866 discloses that, when tone signals are to be sampled and stored in a memory as PCM waveform data, fluctuation (variation) components included in the tone signal are simultaneously detected for the frequency and amplitude and stored into a fluctuation data storage means. When the memory-stored waveform data are to be read out to reproduce the tone signals, the frequency and amplitude fluctuation data are also read out from the fluctuation data storage means, then frequency and amplitude modulations of the read-out waveform data are performed in accordance with the frequency and amplitude fluctuation data, and also the respective depths of these modulations are also controlled. However, the technique disclosed in the No. HEI-5-297866 publication is only arranged to detect, as fluctuation components, frequency and amplitude variation components in the PCM waveform data and perform modulation and control on the detected variation components. Further, Japanese Patent Publication No. HEI-7-82336 discloses detecting a time-varying pitch of each sampled tone signal and storing, into a memory, pitch envelope information indicative of variation over time of the tone pitch on the basis of the detection. In reproducing the tone, a pitch envelope is generated by performing interpolation on the pitch envelope information to appropriately modify the pitch envelope information, and a pitch of the tone to be reproduced is set on the basis of the generated pitch envelope. The technique disclosed in the No. HEI-7-82336 too is only arranged to detect and store variation over time of the tone pitch itself and perform modification/control on the time-varying pitch so that the modified/controlled pitch is used for reproduction of the tone.
The aforementioned conventional techniques can provide high-quality waveform data by sampling a tone performed, for example, on a natural musical instrument, and can also perform, to some extent, control to simulate natural variations of tone elements by detecting and storing, as envelopes, variations over time of tone elements, such as the pitch and amplitude, and then controlling these tone element envelopes at the time of reproduction. However, if envelopes of tone elements, such as a pitch and amplitude, are merely extracted and controlled as taught in the aforementioned conventional techniques, it would be difficult to adjust an expression and degree of humanness of a performed tone. For example, if unison tones or chord tones are polyphonically synthesized using a plurality of waveform data indicative of different characteristics and habits (inclinations) present in pitch and amplitude variations, then pitch intervals between the tones to be synthesized would greatly deviate so that the tones sound like a poor-pitch performance or amplitude expressions of the individual tones undesirably differ from each other. In such a case, the conventional techniques can not make effective adjustments to eliminate the inconveniences. For example, it is conceivable to polyphonically synthesize waveform data of flat characteristics by removing characteristics and habits present in pitch and amplitude variations to convert the pitch and amplitude into flat characteristics; in this case, however, the synthesized tones would become monotonous, losing their individuality as acoustic musical instrument tones.